Instruments, such as electronic meters, of the type enclosed in a generally rigid housing formed of metal or other suitable material, and having a front panel bearing visual displays and/or control devices in various combinations, are well known. Such instruments have been in general use in commercial, industrial and scientific applications for many years. In the most common configuration, the front panels of such instruments are rectangular in shape, and they are fastened to a rectangular box-like housing having side surface portions extending rearwardly from the four edges of the panel in substantially perpendicular relationship. Frequently, the periphery of the rear surface of the front panel is butted against the forward edges of the side surface portions of the housing, and fasteners such as screws pass through the front panel and engage threaded openings in the housing to clamp the panel and the housing together. Most often, a sealing gasket in the form of a rectangular band is clamped between the rear surface of the front panel and the forward edges of the side surface portions of the housing to seal the corresponding joint against entry of dust, moisture and the like.
In a well-known arrangement, a plurality of instruments are mounted in parallel and/or coordinate arrays with the front portion of each instrument projecting slightly forward of a generally planar display "board" that may be positioned vertically or inclined at an angle away from vertical. In other applications, one or more instruments may stand about on table tops or similar support surfaces, close to the sources of the electrical signals that are being controlled and/or displayed.
Applications of the type described above frequently involve substantial amounts of physical activity in relatively close proximity to one or more sensitive instruments. Under such circumstances, various objects being handled by operators, such as heavy tools, test specimens, industrial containers and even other electronic and mechanical instruments, frequently and unavoidably come into unintended contact with the exposed front panels of the instruments being used. The shocks, dents and other damage caused by such unintended contacts can result in substantial financial losses, not only through loss of the instruments themselves, but also through such consequences as lost or invalidated test results, incorrect readings of process control measurements and the like.
Protecting instruments from such damage is considered a highly desirable goal. In addition, especially in applications involving a plurality of instruments that are similar or identical in appearance, it is highly desirable to provide a means for being able to clearly and conveniently distinguish one instrument from another. The need to distinguish is particularly important where similar or identical instruments are reading or controlling signals that are significantly different from one another. In such circumstances, the consequences of mistaking the readings of one instrument for another can result in serious damage and costs.
Accordingly, it is an object of this invention to provide a protective shield for the front panel of electronic instruments and the like capable of absorbing shocks and impacts of unintended blows.
It is another object of this invention to provide a protective shield for the front panel of electronic instruments and the like that easily carries indicia for clearly and conveniently distinguishing one such instrument from another.
Another object of this invention is the provision of an electronic instrument having a front panel guarded by a protective identifying shield.
Another object of this invention is the provision of a protective shield for the front panel of an electronic instrument or the like, that can serve as both a seal between the front panel and an associated case that is mounted in a display board, and as a shield for protecting the case in part by transmitting unintended blows to the display board rather than to the instrument.
Still another object of this invention is the provision of a protective identifying shield for encased electronic equipment such as test instruments and the like that is simple and inexpensive to manufacture, and that can be installed and removed easily without special equipment or extensive labor.